Your symptoms are most likely due to Primolut. As it is a hormone, it can cause all the symptoms that you mention.
tests nowadays are very accurate and if done correctly, the chances of your being pregnant are remote. Scan however cannot detect a very early pregnancy.
I presume you are on Primolut on a doctor's prescription. I do not understand why you have been taking it for 10 days. I would suggest you see your gynaecologist and clarify for what duration you need to take it. In my opinion, you need to stop Primolut and you will get your periods are your symptoms will resolve.